Tool for a bending machine

ABSTRACT

The invention relates to a tool for tube or profile bending machines. At least the surface touching the tube ( 1 ) or profile is coated with a layer of molybdenum or molybdenum alloy, enabling the service life of said tool to be significantly improved.

[0001] The present invention relates to a tool on tube or profilebending machines.

[0002] During the bending of tubes by means of tube bending machines, inwhich the tubes are clamped in place and bent by drawing at the freeend, folds may be produced on the inside of the bend as a result ofupsetting of the material. In order to avoid this, a tool, the foldsmoothing tool, is used for reducing the fold formation. This shapedpiece can have different designs and is occasionally designated as afold smoothing shell or fold smoothing shoe. It supports the tube on theinside of the forming zone in the direction of the part which has justbeen bent. During the bending, the tube is drawn with considerablepressure force via the fold smoothing tool, thereby resulting inconsiderable wear on the fold smoothing tool. To avoid the wear in thefold smoothing tool, it is protected with additional materials, such as,for example, aluminum bronze, beryllium bronze or other bronzematerials. Nonetheless, the fold smoothing tool is impaired to aconsiderable extent and therefore has to be exchanged relativelyfrequently. Tests with lubricants, for example molybdenum lubricant ortitanium nitrite or titanium carbon nitrite, were also unable to produceany substantial prolongation in service life.

[0003] In addition, during bending, mandrels, rollers, guide aids, diesand guide rails are also required, which are likewise highly stressedand therefore also have to be exchanged, even if not so frequently.

[0004] The object of the present innovation is therefore to propose ameans with which the service life of the tools on tube and profilebending machines can be prolonged.

[0005] This object is achieved according to the invention by a tool,such as a fold smoothing tool, mandrel or guide rails, having thefeatures of claim 1.

[0006] Accordingly, a coating of molybdenum or of a molybdenum alloy isapplied to that surface of a fold smoothing tool, a mandrel, rollers,guide aids, dies or guide rails which touches the tube. This coating maybe less than 0.1 mm and nonetheless produces a considerable prolongationin the service life. The molybdenum is applied to the surface by meansof a flame spray process, by electroplating or by vapor deposition.

[0007] A mandrel bending machine for bending tubes is shown in FIG. 1.Here, the bending is effected by drawing the tube 1 by means of a clampdevice 2 by rotating the die 3. A rail 4 and a fold smoothing tool 5provide for the external guidance, and the displaceable mandrel 6arranged in the interior prevents a change in the tube diameter. Thosesurfaces of the rail 4, of the fold smoothing tool 5 and of the mandrel6 which come in contact with the tube are provided with a coating ofmolybdenum or molybdenum alloy.

[0008]FIG. 2, by way of example, shows a fold smoothing tool 5 in whicha protective coating 7 is applied to the surface 8 touching the tube.

1. A tool for tube or profile bending machines, wherein a coating (7) ofmolybdenum or of a molybdenum alloy is applied to at least the surface(8) touching the tube or profile.
 2. The tool as claimed in claim 1,wherein the coating thickness is less than 0.1 mm.